But a lot of Probot's fun comes from listening blind to the whole thing and trying to figure out who's singing what. Among others, D.R.I.'s Kurt Brecht, Voivod's Snake, Lemmy, Celtic Frost's Tom Warrior, Soulfly's Max Cavalera, King Diamond and Cathedral's Lee Dorrian appear. In some cases, it's obvious who's who; in others, it's not so easy to guess. Surprisingly, Grohl didn't always have a particular vocalist in mind when he came up with the foundation of a song. He also didn't interfere creatively once the tapes left his hands, preferring to be surprised by the results.
Probot is no novelty album. But it still makes a great party record -- especially for the slightly aged headbanger. In some cases, Grohl even comes up with material that's more kick-ass than anything the guests' home bands have done in years. All hail Probot!